I was born and brought up in a country where I knew that, on account of my family’s faith, I was barred by law from marrying the sovereign. Not much more than a theoretical hardship, since until recently the law would anyway prevent me as a man from marrying the heirs to the country’s throne because they happen to be male as well. In any case, by the measure of social progress fawningly used at the time of the marriage of Catherine Middleton and William Windsor, I’m still two generations too close to a coal miner.

Nor has any Catholic ever been Prime Minister of the UK. Up to and including Blair’s flirtation with Rome, there was an assumption that, while not strictly illegal, it might be practically difficult or impossible for a Catholic to fulfill the role, given the office’s involvement in church matters.

On the other hand, I grew up knowing that one of America’s greatest presidents was a Catholic, like me. And whether I was first told at primary school or at home, I knew from an early age that John F. Kennedy had given a great and important speech that had persuaded non-Catholic Americans, including Presbyterian and Jewish Americans, that they could safely vote for him without fearing that he was answerable to Rome; or that his decisions in the Oval Office would be made with Catholic doctrine in mind.

In this context, Tim Farron’s stated reasons for resignation are a massive step backwards. There should be no religious disqualification to political office, and Farron’s is self-imposed. If the illiberalism of his church is more important to him than the liberal instinct he claims always to have had, he should have taken some time for private reflection, and in the public sphere worn his religion much more lightly.

I have some sympathy with what seems likeliest to be his position; that whether or not something is a “sin” is a religious rather than a political question, and that he therefore won’t discuss that as a politician. But in how he has, in fact, chosen to answer and not answer the question (as well as in his earliest votes cast on gay rights issues) he has allowed that private religion into his public role.

But it was by using this as justification for his resignation where he did harm. He has explicitly supported the idea that being religious is incompatible with leading a political party with any claim to liberalism. He has projected his own fundamental illiberalism (or at least, his difficulties reconciling his religious and public life) onto others in public life who have personal faith.

We live in a country which has not yet managed fully to reintegrate the Christian sect that I was born into, where the ruling party courts sectarian trouble by seeking the support of the DUP, and where intolerance of Islam is on the march. This is the context in which Tim Farron seems to have confirmed the worst fears of secularists; he has raised the religious bar an inch or two, at least for those who don’t fit the establishment as cosily as do the “sons of the manse” and the “vicars’ daughters.”